Dummy bar for continuous casting

ABSTRACT

This dummy bar is adapted to be connected in axial end-to-end relation to a continuous casting and to be separated therefrom by moving the dummy bar and casting relatively in opposite directions approximately at right angles to an axial line through the connection from the dummy bar to the casting. The end face of the dummy bar which is to be adjacent to the casting is slanted at an acute angle to the directions in which the adjacent ends are separated so as to slant outward toward a casting connected thereto, in the relative direction in which the dummy bar separates from the casting. An insert is slidable in a first slot across the face of the dummy bar in the relative direction in which the dummy bar moves for the separation, and is normally held therein by a shear pin arranged substantially at right angles to the directions of separation and is adapted to shear at a pressure exceeding a predetermined pressure applied for separating the dummy bar and casting. The connection is made by a connecting member having one end adapted to be embedded in the casting and another end slidably received in a second slot which is across the insert in the relative direction in which pressure applies to the dummy bar for the separation.

United States Patent [72] Inventors Walter Hess FOREIGN PATENTS Dusse do 710,250 5/1965 Canada 164/282 Horst Grothe, Kaarst. both of, Germany t 1 [2 I App. No. 736.095 Primary Examiner-J. Spencer Overholser 221 Filed June I, 1968 Assistant Examiner-11 Spencer Anne ar l Paened 20 Attorney-Sand0c, Nell], SchOttlcr & 'WlkStmm [73] Assignee Schloemann Aktiengesellschalt l Prior" fi zz g fg ABSTRACT: This dummy bar is adapted to be connected in y German axial end-to-end relation to a continuous casting and tube P15585138 separated therefrom by moving the dummy bar and castlng relatively in opposite directions approximately at right angles to an axial line through the connection from the dummy bar to the casting. The end face of the dummy bar which is to be ad- [54] DUMMY BAR FOR CONTINUOUS CASTING jacent to the casting is slanted at :an acute angle to the 5 Claims, 6 Drawing Figs dlrections m which the ad acent ends: are separated so as to slant outward toward a casting connected thereto, in the rela- U.S. five direction in which the dummy bar separates from the castl64/232 ing. An insert is slidable in a first slot across the face of the l Int. dummy bar in the relative direction in the dummy bar of Search 89, moves for the eparation and is normally therein a 283 shear pin arranged substantially at right angles to the Reerenm Cited directions of separation and is adapted to shear at a pressure exceeding a predetermined pressure applied for separating the UNITED STATES PATENTS dummy bar and casting. The connection is made by a connect- 3,239,894 3/1966 Masters et al 164/274 ing member having one end adapted to be embedded in the 3,344,844 10/1967 Reinfeld et a1. 164/274 casting and another end slidably received in a second slot 3,372,731 3/1968 Pauels et a1 164/274 X which is across the insert in the relative direction in which 3,464,482 9/1969 Greenberger 164/282 X pressure applies to the dummy bar for the separation.

PATENTEB JULZO l9?! sum 1 OF 2 INVENTORS WALTER HESS HORST GROTHE L'GY aZWM ATTORHEYfi PATENTEU JUL20 nan SHEET 2 OF 2 HORST GRHE ATTORNEYS DUMMY BAR FOR CONTINUOUS CASTING This invention is a dummy bar used in the continuous cast: ing of metal, such as steel. The'invention relates particularly to improved means for connecting the lead end ofa continuously cast strand to a dummy bar at the start of casting, said means being adapted for subsequent disconnection in an improved manner.

In continuous casting, molten metal is poured inthetopof an open-ended chill mold that cools and solidifies the periphery of metal the mold to form a cast strand which emerges from the bottom, exit end, of the mold into a chute; defined by a suitable guide and support means, which'conducts the strand away from the mold. After leaving the mold the casting is further cooled to solidify it completely; it is shaped or otherwise worked before or after complete solidifi cation and is eventually cut into suitable lengths.

At the start of casting, the exit end of the mold is temporarily plugged by a dummy bar until sufficient molten metal accua mulates in the mold for a cast strand to form after which the dummy bar is withdrawn and down the chute in front of the casting. The end of the dummy bar which plugs the mold can: ries a projecting T-headed member around which metal in the mold solidifies to attach the dummy. bar to thelead end of the' casting being formed. After the dummy bar is withdrawn from! the mold, followed by the cast strand emerging continuously. from the mold, additional molten metal is poured into the mold to replenish the metal withdrawn by the casting and to. maintain an appropriate level of metal in the mold for the cast-, ing to continue. Some time after the dummy bar, with the cast-' ing attached, has been withdrawn from the mold it is separated; from the casting and removed from the path of the. casting away from the mold so as not to interfere with, or-complicate subsequent operations performed on the casting.

The connection between the dummy bar and the casting,

must be strong enough for the dummy bar to draw the lead.

end of the casting out of the mold when the dummy bar is? withdrawn from the mold. It is, of course, desirable that the connection be capable of being released as simply and quickly as possible, and with a minimum of damage to either the cast. ing or the dummy bar.

Dummy bars are known in which the connection to the cast ing is provided by sections of rails, or other structural shapes' which have enlarged end portions joined by a relatively thin;

web. These sections are carried in the end of the dummy bar.=

which is to be at the connection, with one enlarged endv slidably received in slots across the end of the dummy bar and the other end projecting outward to become embedded in the casting. The connection is subsequently released for separating the dummy bar from the casting by pressure applied to: move the adjacent ends of the dummy bar and casting relative. ly apart in opposite directions approximately at right angles to: an axial line between the dummy bar and casting so that the: rail sections slide out of the endof theslot in the dummy bar.

Since the initial connection is made by the metal solidifying;

around the projecting ends of the rail sections and against the;

end of the dummy bar, the end of the casting is in intimate contact with the end of the dummy bar. Consequently, with known dummy bars, the sliding friction of the adjacent endswhen these ends are moved relatively apart in the aforesaid manner-is apt to cause sufficient drag for the casting to be bent or otherwise damaged. If, in addition, the molten metal has penetrated the slots in the dummy bar and solidified around the ends of the rail sections therein, the connection;

, may be impossible to release without applying extrapressure;

consuming, particularly in the case of large, heavy dummy bars used for the casting of slabs, and this situation arises frequently enough for it to be a significant and costly problem in continuous casting.

It is therefore an object of this invention to provide a dummy bar in which the release of the connection between the dummy bar and casting involves less sliding friction that in known arrangements, so that the chances of bending or otherwise damaging the casting are substantially eliminated.

Another important object is to provide a connection in which, if the rail sections or other connecting elements are prevented from sliding out of the slots in the dummy bar-due to metal entering and solidifying in the slots, or for any other reason-supplemental connecting means are released by the application of slight additional pressure so as to enable the dummy bar and casting to separate without having to apply much greater additional pressure, or having to use extraordinary measures which would probably damage the casting and would also be likely to damage the dummy bar.

In accordance with the invention, the end face of the dummy bar, which is adjacent to the lead end of the casting when the dummy bar and casting are connected is a plane which is perpendicular to the longitudinal axis of the dummy bar and of the separation force applied to the dummy bar to cause the dummy bar to separate from the casting so that sliding friction of one end across the other is avoided.

As in known dummy bars, the connection is made by one or more connecting members (such as sections of rails), each having one end slidable in a slot in the end face of the dummy bar and another end embedded'in the casting.

In a preferred embodiment of the present invention the ends of the connecting members which are slidable across the end face of the dummy bar are slidably received in slots in inserts, which in turn are slidable in slots in the end face of the dummy bar. The respective slots extend substantially in the directions in which the adjacent ends of the dummy bar and casting separate and are open-ended to permit the connecting members to slide out of the ends of the slots in the inserts, or the inserts to slide out of the end of the slots in the end face of the dummy bar, whenpressure is applied to separate the dummy bar from'the casting. But the inserts are normally retained in the slots in the dummy bar by shear pins which the from the inserts into the walls of the slots in the dummy bar. The shear pins are substantially at right angles to the relative directions in which the dummy bar andcasting separate and are adapted to shear at a pressure exceeding a predetermined pressure applied for separating the dummy bar from the casting. Thus, if the connecting members are locked in the slots in the inserts by solidified metal in the slots, a small amount of additional pressure causes theshear pins to shear in two, thereby releasing the insert which is then'free to slide out of the slats in the dummybar to release the dummy bar from the casting without having ,to use excessive force, or to use other extraordinary means which damage the casting and/or the dummy bar.

An illustrative embodiment of a dummy bar in accordance with the invention, and the operation of the dummy bar, are described below with reference to the accompanying drawings in which:

FIG. 1 is a top plan view of the end ofa dummy bar embodying present invention;

FIG. 2 is a side elevation of an insert which is normally supported in the end face of a dummy bar of the invention, but showing the insert apart therefrom and showing a connecting member in position in the insert;

FIG.' 3 is a vertical section along the line 3-3 of FIG. I;

FIG. 4 is a side elevation ofa portion of one type of continuous-casting apparatus showing the portion at which a dummy bar is separated from a casting;

FIG. 5 is a fragmentary side elevation of a section of another type of continuous-casting apparatus in which the casting undergoes bending after the dummy bar is separated therefrom, the portion shown being the section at which the dummy bar is separated; and

FIG. 6 is a side elevation of a portion of still another type of continuous casting-apparatus in which the dummy bar and casting remain in vertical positions after being separated, said portion being the portion at which the separation is carried out.

Referring to FIGS. 1, 2 and 3, at the start of a continuouscasting run a dummy bar is connected to the lead end 11 of a continuouscasting 12, by one or more connecting members 13. Each connecting member 13 has enlarged ends 13a and 13b joined by a relatively thin web portion 13c and is suitably provided by a section of rail. The ends 13a are slidably received in matching slots 14 in the end face 15 of the dummy bar 10 which is adjacent to the lead end 11 of the casting 12 for the connection; the opposite ends 13b are embedded in the casting. In FIG. I the casting 12 is a broad slab for which a number of connecting members 13 are appropriately provided along the end face of the correspondingly dimensioned dummy bar. The number and spacing of connecting members 13 provided depends upon the dimensions of the casting and dummy bar. In some cases one will be enough.

For separating the dummy bar and casting they are moved relatively in opposite directions, indicated by arrows 16 and 17, approximately at right angles to an axial line between them through the connection. The slots 14 extend in the directions of relative movement of the casting and dummy bar so that, in the ideal situation, the ends 130 slide out the ends of the slots 14 to free the dummy bar. The connecting members 13 remain embedded in the casting 12 and may subsequently be removed by cutting off the end of the casting.

The release of the dummy bar 10 from the casting 12 is conventionally facilitated by placing a sheet 18 of asbestos or the like and an overlaying sheet 19 of metal on the end face 15, which is at the connection, the sheets 19 and 18 being appropriately cut out and fitted around the connecting members 13.

In accordance with this invention the end face 15 of the dummy bar is slanted at an acute angle to the direction of the separation this direction force applied to the dummy bar, this direction being indicated by arrow 16. Thus, it will be seen that when dummy bar 10 and casting 12 are move relatively apart by separation forces applied in the direction of arrows 16 and l7-either one or both of the dummy bar and casting being moved relative to the other by appropriately applied pressure-the end face 15 of the dummy bar and the corresponding adjacent face of the lead end 11 of the casting 12 move out of contact with each other immediately as the movement starts, thereby avoiding sliding friction of one face across the other.

In accordance with a preferred form of the invention each slot 14 in the end face 15 of the dummy bar 10 is in an insert 20 which is itself slidable in a slot 21 in the end face 15 of the dummy bar. Like the slot 14, the slot 21 extends in the direction of relative movement of the casting and dummy bar and at least one end of the slot 21 (the bottom end) opens through the side of the dummy bar 10 to permit the insert 20 to slide out the end of the slot 21 to free the dummy bar 10 from the casting 12 if the end 13a of connecting member 13 sticks in slot 14 when the dummy bar and casting are moved relatively apart.

The inner portion of the slot 21 is enlarged (as best seen in FIG. 1) in comparison with a relatively narrower neck portion opening through the end face 15 of the dummy bar and has shoulders 22 between the neck and inner portion facing inward. The shape of theinsert 20 corresponds to the shape of the slot 21 and has shoulders 23 to slidably engage shoulders 22 when the insert is in position in the slot 21. The insert 20 is dimensioned to provide good clearance within the slot 21 so as to allow for thermal expansion and enable it to slide easily in slot 21. However, the insert 20 is normally held in the slot by one or more shear pins 25 having their ends mounted respectively in the insert 20 and dummy bar 10 and extending substantially at right angles to the directions (arrows l6 and 17) in which the dummy bar 10 and casting 12 separate. In the drawings the shear pins 25 are shown extending between the insert and dummy bar through the respective shoulders 22 and 23. The'shear pins 25 are dimensioned to shear off, and free the insert to slide out of the slot 21, at a pressure in excess of the pressure normally required to slide the end 1311 of the connecting member 13 out of the slot 14 when the dummy bar 10 and casting 12 are moved relatively apart and when nothing such as metal in the slot 14 locking the end 13a thcreinobstructs the sliding of the end 13a. Thus, if the separation of the dummy bar and casting by application of usual pressure for separating is hampered by the end 13a of the connecting member 13 sticking in the slot 14, the application of slight additional pressure is adapted to shear the shear pin 25 so that the insert 20 is freed to slide out of the slot 21 so that the dummy bar 10 separates from the casting 12 without having to resort to extraordinary measures which might be time consuming and which would most likely necessitate damaging the casting and the dummy bar.

As most clearly shown in FIGS. 2 and 3, the faces of the shoulders 22 and 23 are slanted oppositely from the slant of the end face 15 of the dummy bar 10. That is, the shoulders 22 and 23 slant at an acute angle to the directions ofseparation of the dummy bar and casting (indicated by arrows 16 and 17), but slant inward, away from the casting 12, in the relative direction in which the dummy bar separates from the casting (arrow 16).

FIGS. 4, 5 and 6 illustrate the operation of a dummy bar, which embodies this invention, in the portions of three different types of continuous-casting apparatus in which the dummy bar 10 is separated from the casting 12 by relative movement in opposite directions (arrows 16 and 17 in FIGS. 1 to 3).

In the apparatus illustrated in FIG. 4, the dummy bar 10, with a casting 12 connected thereto, moves in a horizontal direction, passing through a bank of withdrawal and straightening rolls 30 and moving to the right until the junction between the dummy bar 10 and casting 12 is in a disconnecting mechanism 31 consisting of a pair of fixed rollers 32 for holding the lead end 11 of the casting 12, and an upwardly movable pressure cylinder 33 for lifting the (rear) end of the dummy bar 10 up so that the end face 15 of the dummy bar moves up and away from the lead end 11 of the casting. In this apparatus, the dummy bar 10-whose forward end is at an angle to the rearward end which is connected to a casting 12- is received in an elongated housing 34 which is normally arranged at an angle to intersect the path of the dummy bar. The forward (right) end of the housing 34 is supported on a roller 35 and its rearward (right) end is moved up and down by a cable 36 passing over an idler pulley 37 and connected to a piston 38 which is moved up and down by a suitable pressure cylinder for raising and lowering the housing 34. When the dummy bar 10 has been disconnected from the casting by upward movement of the pressure cylinder 33, the piston 38 and cable 36 are operated to raise the housing 34. The forward end of the housing rocks on the roller 35, and the housing with the dummy bar 10 therein is raised to the position indicated in dashlines. In this position the end face 15 of the dummy bar is in position for a worker 39 on a platform 40 to insert a new connecting member 13 in the insert 20 in the end face 15 of the dummy bar (or otherwise condition the end face 15) to prepare the dummy bar for use in a subsequent casting run. The dummy bar 10 is drawn into, and let out of, the housing 34 by a cable 41 attached to the lead end of the dummy bar and passing over an idler pulley 42, which is mounted on the forward end of the housing, and wound on a power-driven drum indicated at 43. After the dummy bar 10 has thus been lifted up in the housing 34, the casting I2 continues in a horizontal path, illustrated in dash lines.

In the apparatus shown in FIG. 5 the dummy bar 10 and casting 12 moves vertically down. In this case the dummy bar is held in a vertical path by a thrust block 45 and the lead end 11 of the casting 12 is moved to one side (to the left) by a laterally movable pressure roller 46. As indicated, the pressure roller 46 moves to the position shown in dashlines to deflect the casting into a curved pathshown by the dashline position of the casting 12-defined by the guide roller 43. The thrust block 45 is carried on bracket 47 which is movable in a vertical path. As the dummy bar 10 moves down from the disconnecting point, the bracket 47 and thrust block 45 move down with it, to the lower position indicated in dashlines, in order to provide continuing vertical support for the dummy bar.

In the apparatus illustrated in FIG. 6 the dummy bar It), and casting 12 move vertically down between pairs ot'guide rollers 49 with the lowermost end of the dummy bar (and subsequently the lowermost end of the casting) supported on a carriage 50, which is movable vertically on rails 51 to guide and support the dummy bar (or casting) ina downward vertical path. When the junction of the dummy bar and casting are below the lower pair of guide rollers 49, the dummy bar is disconnected by a laterally movable pressure roller 52, which is operated to move the upper end of the dummy bar to the leftin concert with a resiliently supported counter roller 53 in a support 54. After the dummy bar is thus disconnected, it is moved down by the carriage 50 until it is in position to be grasped by a pair of gripping jaws 55 on a carriage 56 which is movable horizontally on a track indicated at 57. When the dummy bar is in the gripping jaws 55, the carriage 56 moves to the left to carry the dummy bar out of the vertical path of the casting 12. The pressure roller 52 and counter roller 53 return to the right and'the downward movement of the casting I2 is continued. The vertically movable carriage 50 is moved up to engage and support the lead end I] of the casting and is then moved down to support and guide the casting in a downward vertical path indicated in dashlines.

What we claim is:

1. A dummy bar adapted to be connected in axial end to end relation to the lead end of a continuous casting and to be separated therefrom by moving the dummy bar and casting relatively in opposite directions approximately at right angles to an axial line through the connection from the dummy bar to the casting, the end face of the dummy bar, which is to be at the connection, being slanted at an acute angle to a plane which is perpendicular to the longitudinal axis of the dummy bar and to the direction of the separation force applied to the dummy bar to cause the dummy bar to separate from the castmg. a

2. The dummy bar of claim I, and in combination, an insert slidably received in a first slot in said face end of the dummy bar. said slot extending across said face in the approximate directions in which the adjacent ends of the dummy bar and casting separate, the ends of the slot being open through the sides of the dummy bar for the insert to slide out, a shear pin having its ends mounted substantially at right angles to the directions of separation of the dummy bar and casting for attaching the insert in the slot, said shear pin being adapted under a pressure exceeding a predetermined pressure applied for separating the dummy bar and casting, a connecting member having one end adapted to be attached to a casting adjacent to said end face of the dummy bar and another end slidably received in a second slot in said insert for connecting the casting to the dummy bar, said second slot extending across the insert in the approximate relative directions in' which the dummy bar and castingse'parate, said second slot having an end open through one side of the insert for said other end of the connecting member to slide out and free the connecting member from said second slot when the dummy bar and casting are moved relatively in opposite directions for separating them, said other end of the connecting member being adapted normally to slide along side second slot when said predetermined pressure is applied for separating the dummy bar and casting.

3. The dummy bar of claim 2 in which said slot in the end face of the dummy bar has an enlarged inner portion along its length and a relatively narrow portion along its length opening through said end face with shoulder portions between said portions at each side of the slot, said shoulders having relatively flat surfaces facing inward toward the bottom of the slot and extending the length of the slot, said insert in the slot having shoulder portions for engaging and sliding on the shoulders of the slot, whereby the cooperating shoulders of the slot and insert confine the insert in the slot for sliding movement along the length of the slot.

4. The dummy bar of claim 3 in which said cooperating shoulders of the slot and insert are slanted oppositely from the slant of the end face of the dummy bar.

5. The dummy bar of claim 4 including more than one of said inserts in slots spaced along the length of the face end of the dummy bar with a shear pin and connecting member for each insert. 

1. A dummy bar adapted to be connected in axial end to end relation to the lead end of a continuous casting and to be separated therefrom by moving the dummy bar and casting relatively in opposite directions approximately at right angles to an axial line through the connection from the dummy bar to the casting, the end face of the dummy bar, which is to be at the connection, being slanted at an acute angle to a plane which is perpendicular to the longitudinal axis of the dummy bar and to the direction of the separation force applied to the dummy bar to cause the dummy bar to separate from the casting.
 2. The dummy bar of claim 1, and in combination, an insert slidably received in a first slot in said face end of the dummy bar, said slot extending across said face in the approximate directions in which the adjacent ends of the dummy bar and casting separate, the ends of the slot being open through the sides of the dummy bar for the insert to slide out, a shear pin having its ends mounted substantially at right angles to the directions of separation of the dummy bar and casting for attaching the insert in the slot, said shear pin being adapted under a pressure exceeding a predetermined pressure applied for separating the dummy bar and casting, a connecting member having one end adapted to be attached to a casting adjacent to said end face of the dummy bar and another end slidably received in a second slot in said insert for connecting the casting to the dummy bar, said second slot extending across the insert in the approximate relative directions in which the dummy bar and casting separate, said second slot having an end open through one side of the insert for said other end of the connecting member to slide out and free the connecting member from said second slot when the dummy bar and casting are moved relatively in opposite directions for separating them, said other end of the connecting member being adapted normally to slide along side second slot when said predetermined pressure is applied for separating the dummy bar and casting.
 3. The dummy bar of claim 2 in which said slot in the end face of the dummy bar has an enlarged inner portion along its length and a relatively narrow portion along its length opening through said end face with shoulder portions between said portions at each side of the slot, said shoulders having relatively flat surfaces facing inward toward the bottom of the slot and extending the length of the slot, said insert in the slot having shoulder portions for engaging and sliding on the shoulders of the slot, whereby the cooperating shoulders of the slot and insert confine the insert in the slot for sliding movement along the length of the slot.
 4. The dummy bar of claim 3 in which said cooperating shoulders of the slot and insert are slanted oppositely from the slant of the end face of the dummy bar.
 5. The dummy bar of claim 4 including more than one of said inserts in slots spaced along the length of the face end of the dummy bar with a shear pin and connecting member for each insert. 